diff -Naur linux.orig/drivers/net/loopback.c linux/drivers/net/loopback.c
--- linux.orig/drivers/net/loopback.c	2004-05-21 11:00:24.000000000 -0700
+++ linux/drivers/net/loopback.c	2004-05-21 11:04:00.000000000 -0700
@@ -123,7 +123,9 @@
  */
 static int loopback_xmit(struct sk_buff *skb, struct net_device *dev)
 {
-	struct net_device_stats *stats = dev->priv;
+	struct net_device_stats *global_stats = dev->priv;
+	struct net_device_stats *percpu_stats = 0;
+	struct net_device_stats *local_stats  = 0;
 
 	skb_orphan(skb);
 
@@ -142,11 +144,13 @@
 	}
 
 	dev->last_rx = jiffies;
-	if (likely(stats)) {
-		stats->rx_bytes+=skb->len;
-		stats->tx_bytes+=skb->len;
-		stats->rx_packets++;
-		stats->tx_packets++;
+	if (likely(global_stats)) {
+		percpu_stats = global_stats + 1;
+		local_stats  = &percpu_stats[smp_processor_id()];
+		local_stats->rx_bytes+=skb->len;
+		local_stats->tx_bytes+=skb->len;
+		local_stats->rx_packets++;
+		local_stats->tx_packets++;
 	}
 
 	netif_rx(skb);
@@ -156,7 +160,22 @@
 
 static struct net_device_stats *get_stats(struct net_device *dev)
 {
-	return (struct net_device_stats *)dev->priv;
+	int i;
+	struct net_device_stats *global_stats = dev->priv;
+	struct net_device_stats *percpu_stats = 0;
+
+	if (global_stats) {
+		percpu_stats = global_stats + 1;
+		/* zero the system-wide stats */
+		memset(global_stats, 0, sizeof(struct net_device_stats));
+		for ( i = 0; i < NR_CPUS; i++ ) {
+			global_stats->rx_bytes   += percpu_stats[i].rx_bytes;
+			global_stats->tx_bytes   += percpu_stats[i].tx_bytes;
+			global_stats->rx_packets += percpu_stats[i].rx_packets;
+			global_stats->tx_packets += percpu_stats[i].tx_packets;
+		}
+	}
+	return global_stats;
 }
 
 struct net_device loopback_dev = {
@@ -181,13 +200,19 @@
 {
 	struct net_device_stats *stats;
 
+#define NR_LOOP_STATS (NR_CPUS + 1)
+	/* the first net_device_stats structure is for the whole system, the 
+	 * remaining NR_CPUS of them are for each cpu */
+
 	/* Can survive without statistics */
-	stats = kmalloc(sizeof(struct net_device_stats), GFP_KERNEL);
+	stats = kmalloc(NR_LOOP_STATS * sizeof(struct net_device_stats), GFP_KERNEL);
+
 	if (stats) {
-		memset(stats, 0, sizeof(struct net_device_stats));
+		memset(stats, 0, NR_LOOP_STATS * sizeof(struct net_device_stats));
 		loopback_dev.priv = stats;
 		loopback_dev.get_stats = &get_stats;
 	}
+#undef  NR_LOOP_STATS
 	
 	return register_netdev(&loopback_dev);
 };
diff -Naur linux.orig/net/core/dev.c linux/net/core/dev.c
--- linux.orig/net/core/dev.c	2004-05-21 11:01:01.000000000 -0700
+++ linux/net/core/dev.c	2004-05-21 11:03:44.000000000 -0700
@@ -1295,6 +1295,7 @@
 	struct net_device *dev = skb->dev;
 	struct Qdisc *q;
 	int rc = -ENOMEM;
+	int loopback = dev->flags & IFF_LOOPBACK;
 
 	if (skb_shinfo(skb)->frag_list &&
 	    !(dev->features & NETIF_F_FRAGLIST) &&
@@ -1322,17 +1323,19 @@
 	}
 
 	/* Grab device queue */
-	spin_lock_bh(&dev->queue_lock);
-	q = dev->qdisc;
-	if (q->enqueue) {
-		rc = q->enqueue(skb, q);
+	if (!loopback) {
+		spin_lock_bh(&dev->queue_lock);
+		q = dev->qdisc;
+		if (q->enqueue) {
+			rc = q->enqueue(skb, q);
 
-		qdisc_run(dev);
+			qdisc_run(dev);
 
-		spin_unlock_bh(&dev->queue_lock);
-		rc = rc == NET_XMIT_BYPASS ? NET_XMIT_SUCCESS : rc;
-		goto out;
-	}
+			spin_unlock_bh(&dev->queue_lock);
+			rc = rc == NET_XMIT_BYPASS ? NET_XMIT_SUCCESS : rc;
+			goto out;
+		}
+	} /* !loopback */
 
 	/* The device has no queue. Common case for software devices:
 	   loopback, all the sorts of tunnels...
@@ -1354,11 +1357,13 @@
 			 * The spin_lock effectivly does a preempt lock, but 
 			 * we are about to drop that...
 			 */
-			preempt_disable();
-			spin_unlock(&dev->queue_lock);
-			spin_lock(&dev->xmit_lock);
-			dev->xmit_lock_owner = cpu;
-			preempt_enable();
+			if (!loopback) {
+				preempt_disable();
+				spin_unlock(&dev->queue_lock);
+				spin_lock(&dev->xmit_lock);
+				dev->xmit_lock_owner = cpu;
+				preempt_enable();
+			}
 
 			if (!netif_queue_stopped(dev)) {
 				if (netdev_nit)
@@ -1366,13 +1371,17 @@
 
 				rc = 0;
 				if (!dev->hard_start_xmit(skb, dev)) {
-					dev->xmit_lock_owner = -1;
-					spin_unlock_bh(&dev->xmit_lock);
+					if (!loopback) {
+						dev->xmit_lock_owner = -1;
+						spin_unlock_bh(&dev->xmit_lock);
+					}
 					goto out;
 				}
 			}
-			dev->xmit_lock_owner = -1;
-			spin_unlock_bh(&dev->xmit_lock);
+			if (!loopback) {
+				dev->xmit_lock_owner = -1;
+				spin_unlock_bh(&dev->xmit_lock);
+			}
 			if (net_ratelimit())
 				printk(KERN_CRIT "Virtual device %s asks to "
 				       "queue packet!\n", dev->name);
@@ -1385,7 +1394,8 @@
 				       "%s, fix it urgently!\n", dev->name);
 		}
 	}
-	spin_unlock_bh(&dev->queue_lock);
+	if (!loopback)
+		spin_unlock_bh(&dev->queue_lock);
 out_enetdown:
 	rc = -ENETDOWN;
 out_kfree_skb: